<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>网上书城--登录界面</title>
    <style type="text/css">
        body{
            margin: 0px;padding: 0px;
        }
        div{
            font: bold 22px 行书;
            color: cyan;
            text-align: center;
            text-decoration: underline;
        }
        #container{
            width: 100%;padding: 0px;
        }
        #header{
            width: 100%;height: 80px;background: purple;
        }
        #content{
            width: 100%;height: 200px;background: darkred;
        }
        #footer{
            width: 100%;height: 80px;background: darkorange;
        }
    </style>
</head>
<body>
      <div id="container">
          <div id ="header">header我就随便写几个字</div>
          <div id="content">content</div>
          <div id="footer">footer</div>
      </div>

</body>
</html>